1. Field of the Invention
The present invention relates to an electric pump comprising an impeller coupled via a shaft to at least one permanent magnet rotor of an electric motor, and a hermetically sealed housing in which the shaft is supported and which has as sole openings the delivery side and suction side connections for the material to be pumped.
2. Background Information
The present invention specifically relates to powerful pumps having an electrical power in the range of 10 kW and more. When installing such powerful pumps in a piping system, the drive for the pump unit proper is provided in the form of a motor flange-mounted to the outside of the pump housing.
Pump aggregates with a power in the above-indicated range are heavy and bulky. They require specific support on a foundation. Direct, freely supported integration in the piping system is not possible with the known pumps.
There are specific legal regulations concerning the design of pumps, in particular pumps used for environmentally hazardous fluids. It must be ensured that leakage of environmentally hazardous fluids is prevented. This leads to specific problems with respect to the sealing of the shaft passage. In the known pumps, the rotary shaft left the pump housing at at least one location of the housing. This is where special sealing measures must be taken.
There was already suggested an electric pump of the type indicated at the outset, in which measures are taken for preventing that the shaft extends out of the pump housing. To this end, the known electric pump is provided with a housing enclosing the electric motor, the drive shaft and the pump impeller located on the drive shaft. This pump complies with the legal requirements and avoids complex sealing measures; for, as the shaft does not leave the housing at any location, the pumping material has virtually no possibility to get out of the housing.